The long-term objective of this project is to study the genetics and biogeography of phlebotomine sand flies (Diptera: psychodidae). Little is known about the genetics of this important insect group, members of which serve as vectors of leishmaniasis, bartonellosis and a number of arboviral diseases. Initial studies will focus on Lutzomyia longipalpis and L. shannoni, two species which have been implicated as vectors of leishmaniasis and which have a very wide geographic range in the Americas. The proposed project involves both field and laboratory studies. Representative field collections of L. longipalpis and L. shannoni will be made throughout their geographic ranges; biochemical and morphological keys to both species will be developed as well as various geographic parameters of their distribution. Genetic profiles for each collection will be constructed using enzyme electrophoresis. Distinct geographic and genetic populations of L. longipalpis will also be compared for their susceptibility to infection with Leishmania chagasi, the etiologic agent of New World visceral leishmaniasis. Genetic maps will be constructed for the two medically important sand fly genera (Lutzomyia and Phlebotomus), based on biochemical markers, chromosome numbers, recombination frequencies and linkage maps. The latter work will utilize laboratory colonies of sand flies maintained at the Yale Arbovirus Research Unit. The project is a collaborative effort between scientists at Yale University and the Instituto Nacional de Salud in Bogota, Colombia, but a number of other sand fly specialists in the U.S. and Latin America will assist with the field collections.